Apparatus and methods for storing and dispensing solid material

ABSTRACT

The invention is directed to a dispensing unit suitable to precisely dispense material in powdery and/or granular form. The dispensing device comprises an gate valve opening sealingly closed by a blend. A control unit, which is interconnected to a scaling device, controls the opening of the gate valve opening by the position of the blend. The precise amount of the material is adjusted in relation to the signal of the scaling device.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.11/131,975, filed May 18, 2005, which is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to an apparatus and a method fordispensing material, especially small amounts of solid material inpowdery or granular form.

BACKGROUND OF THE INVENTION

In various industries, such as the chemical and the pharmaceuticalindustry handling of non-liquid materials in solid or powdery form isused for preparing mixtures, drugs, tests, in-process products or finalproducts. Several dispensers for handling powdery materials are knownfrom prior art and it is inherent to those devices that in general theyare not suitable to precisely dispense different amounts of material,especially when the amount of material to be dispensed is small (e.g. inthe range of milligrams). Most important, these devices are not suitableto dispense powdery materials if the starting amount is very limited,such as e.g. 30 mg or less. However, in the chemical and thepharmaceutical industry, for research, development and production, it isimportant to be able to precisely dose small and very small amounts ofpowders and solids, with different flow characteristics and independentof the starting amount.

DESCRIPTION OF PRIOR ART

U.S. Pat. No. 5,145,009 is directed to an apparatus for metering dry andpulverulent pourable material such as dye powder in a laboratory dyeingline for textiles. The apparatus includes a discharge container whichhas a closable outlet in its lower region. Scales for metering theamount of material that is to be conveyed from the outlet of thecontainer are arranged on the underside of the container. The containerincludes a valve body that tapers towards the top and can be displacedvertically downwards. The valve body is arranged rotatable in closed andopen position having the capability for conveying the material in thedirection towards the outlet opening therefore performing a dualfunction. One disadvantage consists in that the device is not suitablefor small amounts of material.

WO02/29371 is directed to a dosing unit for releasing a powderysubstance and a scale for determining the amount of substance released.The dosing unit comprises a storage container that contains thesubstance to be released and is mounted on a scale in such a way thatthe scale measures the weight of the dosing unit. As the scale measuresthe weight of the dosing unit including the storage container and thesubstance, the amount of the substance released can be determined bysubtraction.

WO03/098170 discloses a device for dosing powdery substances. The devicecomprises a substance-receiving device which is provided with aplurality of compartments suitable to receive a substance that is to bedosed and which can be emptied individually. The device also comprisesan evacuation device for emptying the compartments, a scale determiningthe quantity of dosed substance and means for controlling the evacuationof the compartments according to the quantity of the dosed substance.

WO2005/002654 is directed to a device for dispensing individual doses ofpowder from pockets of a disc-shaped carrier. The doses are dispensed byrupturing a foil by pressure on an opposite side surface. The deviceprovides individual flow paths for each pocket. Split airstreams areallowing improved entrainment of powder and a cam mechanism is providedfor outwardly rupturing the pockets. Further an indexing mechanism islinked to the cam mechanism and a dose counter.

US2005/0040185 describes an apparatus for dispensing small quantities ofparticles. The apparatus comprises a hopper provided with a sieve at abottom portion thereof. The hopper defines a powder-containing zoneabove the sieve which in use contains powder to be dispensed therefromthrough the sieve. The hopper is held by a support so that the hoppercan in use be held above a container into which the dispensed powder isto be received. At least one actuator is provided for delivering impactenergy to the hopper for causing powder to be dispensed through thesieve when the hopper receives the impact energy.

WO03/026965 is from the same applicant as US2005/0040185 and alsodescribes an apparatus for dispensing small quantities of particles. Theapparatus comprises a hopper provided with a sieve at a bottom portionthereof. The hopper defines a powder-containing zone above the sievewhich in use contains powder to be dispensed therefrom through thesieve. The hopper is held by a support so that the hopper can in use beheld above a container into which the dispensed powder is to bereceived. At least one actuator is provided for delivering impact energyto the hopper for causing powder to be dispensed through the sieve whenthe hopper receives the impact energy. The actuator is arranged todeliver impact energy to the hopper from different directions and/or atdifferent locations on the hopper.

WO2005/014397 describes a method and an apparatus for filling acontainer with powder in that an outlet of a hopper containing powder ispositioned above an open end of the container. The hopper ismechanically agitated so as to cause powder to be transferred from thehopper to the container. By mechanically agitating the container it isensured that the container is filled with powder at a predetermineddensity.

U.S. Pat. No. 6,805,175 describes an apparatus for aspirating anddispensing powder. The apparatus comprises hopper having a powdertransfer port and a suction port for connection to a source of suctionto establish an upward flow of air through the transfer port. A gas flowcontrol system varies the upward flow through the transfer port atdifferent velocities, whereby the velocities include an aspiratingvelocity for aspirating powder into the hopper through the transfer portto form a fluidized bed of powder in the hopper, and a dispensingvelocity less than the aspirating velocity but sufficient to maintainfluidization of the bed while allowing powder from the bed to gravitatethrough the transfer port for dispensing into one or more destinationreceptacles. A method of aspirating and dispensing powder is alsodisclosed.

WO02/11800 discloses a powder delivery device for the delivery of aphysiologically active agent in powdered form into a patient's nasalcavity. The device comprises a bulk reservoir for containing multipledoses of powder, a powder delivery passage for the forced flow of gaswith a dose of said powder entrained therein to a patient. A powdermetering unit for metering out a dose of powder from said bulk reservoiris provided to align a metered dose with said gas flow passage.

WO03/066437 is directed to a method and an apparatus for introducingpowder into a pocket using a dosator. The dosator includes an elongatecavity with an open end and a plunger opposite the open end moveablealong the cavity so as to define a space of variable volume. The plungerdefines a volume which is greater than that of the pocket. By insertingthe open end of the dosator into a source of powder the volume is filledwith powder. By positioning the open end over the pocket and driving theplunger the powder is expelled from the open end into the pocket andcompressed to a predetermined bulk density.

US2001/0027823 discloses a dispensing apparatus for granular or powderybulk materials. The apparatus includes a balance to weigh doses ofmaterial being dispensed, a reservoir container and a cover to close adownward-facing opening of the reservoir container. A conveying anddelivering device is integrated in the cover. The conveying anddelivering device has a vertically movable, rotary conveyor bodydesigned so that it can substantially close off the dispensing outletfor the bulk material. The conveyor body has a ring-shaped bottom and aring-shaped conveyor channel which is recessed in the cover. The outletis arranged in the ring-shaped channel and is designed to deliver adirected and locally concentrated stream of bulk material.

WO02/090896 is directed to a powder measure-dispensing cap. Thedispensing cap comprises a body with a feed opening. The feed opening issupplied by at least one endless screw.

GB1488719 describes a dispenser for dispensing liquids or powderymaterials out of an aerosol container in which the liquids or powderymaterials are stored together with a propellant.

CA2100046 discloses a disposable dispensing device for dispensing solidmaterials in powder or granular form. The dispensing device dispensesmeasured quantities without using a teaspoon or other separate measuringdevice. The device comprises a longitudinal passage and a sliding memberwith a substantially rectangular cross-section. The sliding member ismovable from a first position to a second position such that a dispenseraperture may be opened or closed.

CA2250574 discloses a dispenser for substances in powder or granularform. The dispenser enables a multiplicity of doses of a substance inpowder or granular form contained in a reservoir to be dispensed insuccession. To form a dose a shaft must be rotated relative to a part ofthe dispenser, whereby the shaft has to be arranged substantiallyvertical while the dose is being formed. It is not foreseen to dispenseindividual amounts of materials.

U.S. Pat. No. 5,573,340 describes a device for dispensing a liquid orpowdery product. This device includes a container and a stopper forsealing the container. A pouch made of an elastic substance with a slitis placed inside the neck of the container. The slit is open when astopper seals the container. The slit closes when the stopper is removedfrom the container.

U.S. Pat. No. 3,662,930 is directed to a dispensing package for adding amedicine to a parental solution container which is characterized by aplug disposed between a medicament reservoir and a discharge conduit.The plug has a labyrinth through which solid medicament must pass ondischarge. The function of the labyrinth is to prevent the additivepowder from being spilled or misdistributed out of the package.

From the prior art devices are known wherein predetermined amounts ofmaterial are encapsulated in appropriate standardized containers orcapsules of different sizes made out of an inert material such as glass.With these devices the minimum amount possible to be dispensed is givenby the smallest standardized container available and a fine graduationis therefore difficult to achieve. A further disadvantage is thelogistic effort necessary to produce, handle and store the differentcontainers. Still a further disadvantage consists in that the remains ofthe containers have to be disposed or separated form the mixtures.Prepacked containers comprising different materials to be dispensed maybe mistaken for one another. Therefore it is important that the risk oferror is at least minimized if not completely avoided.

The dispensers known from prior art are not suitable for automaticdispensing of small starting amounts of materials into typically usedvessels and receptacles, such as plates, vials, bottles, capsules, etc.,in very low quantities, like 1 mg or less. One reason for this problemis that the known devices are too large or have too many parts involvedsuch that, due to the large surface of the parts involved, smallquantities of powder cannot be handled well by the known devices. Also,the waste of the powder caused by the known devices is considerable.Another draw back is that the devices known from prior art in generalconsist of a large number of parts which are difficult to manufacture,assemble, maintain and clean. A further draw back is that the devicesknown from prior art have to be adjusted according to the physicalcharacteristics of the material to be dispensed or cannot be used fordispensing of cohesive powders. In addition, the known devices may losepowder during operation because they are not sufficiently sealed.Uncontrolled loss of powder may cause serious problems andcontamination.

PROBLEM TO BE SOLVED

It is one object of the invention to provide a device which is suitableto precisely dispense small and very small amounts of at least onematerial in powdery or granular form, especially when the startingamount is limited. It is a further object of the invention to provide adevice that prevents negative contamination, spilling or loss ofmaterial. It is a further object of the invention to provide a devicewhich allows recovering remaining powder without negative loss. It is afurther object of the invention to provide a device for automaticallydispensing at least one material in powdery or granular form. It isstill a further object to provide a device which is suitable to reducethe risk of dispensing errors.

SUMMARY OF THE INVENTION

One embodiment of the invention comprises a dispensing device which has,compared to the devices known from prior art, a simple setup suitablefor being made of metal or injection molded plastic, depending on whatis desired in view of the field of application. The device is easy tofill and empty without the need of extensive cleaning. A limited numberof parts are in direct contact with the material to be dispensed. Theseparts are easy to clean and to maintain. Compared to the prior art, oneadvantage is that the device offers the possibility for miniaturizationwhich facilitates handling small amounts of material. The device isfurther suitable for use with materials in powdery and/or granular formhaving different physical characteristics (e.g. particle size, shape andform, density, humidity). The device further provides a high repeatingaccuracy (such that it is possible to dispense thirty portions of 1 mgor sixty portions of 0.5 mg, for example) with a high accuracy using asingle dispenser. Therefore the dispenser according to the presentinvention is especially suitable to be used in laboratories (e.g. of thepharmaceutical and biotechnological industry) and particularly forsmall-scale scientific research. The device limits the risk ofcross-contamination since the openings can be sufficiently sealed ifnecessary.

To provide a high accuracy the device preferably comprises or isinterconnectable to at least one scaling means to directly or indirectlymeasure the amount of material dispensed. For direct measuring thescaling device is interconnected to the dispensing device itself,measuring the amount of material leaving the dispensing device.Alternatively or in addition the scaling device, for indirect measuring,is interconnected to the container determined to receive the dispensedmaterial.

The dispensing device in general comprises at least one compartment toreceive a material to be distributed, a gate valve, preferably a gatevalve with variable opening, an agitator, and a conveyor. The gatevalve, the agitator and the conveyor are driven by at least one drivemechanism which forms part of the dispensing device or to which thedispensing device may be interconnected by interfaces. In a preferredembodiment the agitator and the conveyor are incorporated in a singledevice. Depending on the field of application the dispensing devicefurther comprises a storing means to hold information about the materialcontained in the dispensing device temporarily or permanently (e.g. thetype of material, amount of material and condition of the materialcontained in the dispensing device). If appropriate the dispensingdevice may further comprise at least one sensor to retrieve informationabout the condition of the material contained in the dispenser, such ashumidity, temperature or electric conductivity.

A control unit which may form part of the dispensing device or to whichthe dispensing device may be interconnected controls the position andopening of the gate valve, the agitator and/or the conveyor. The controlunit is, if present, further interconnected to the at least one scalingmeans to control or double check the amount dispensed from thedispensing device. The control unit may further comprise means to readout and store information from the storing means.

In a preferred embodiment the dispensing device is designed as anexchangeable unit having a first standardized interface suitable to beinterconnected with an appropriate second standardized interface of acontroller. The controller is thereby suitable to receive differentdispensing devices, e.g. of different size or containing differentmaterials. When not interconnected to the controller the differentdispensing devices are preferably stored in a storing unit tightlysealed. Exchanging of the dispensing devices preferably takes place byan exchanging device which is suitable to exchange the dispensingdevices automatically.

Due to the large flexibility and the setup it is possible to provide anadapter means by which the dispensing device according to the presentinvention may be interconnected to existing control devices as knownfrom the prior art. The adapter means is foreseen to transfer controlvariables and if appropriate feedback information between the dispensingdevice and the control device for adjusting the opening of the gatevalve.

For handling small amounts of solid material, e.g. in powdery orgranular form, it can be important that no needless waste and spillingof material takes place. One source of misspending with the devicesknown from the prior art often takes place in the area of the dispensingopening. The dispensing device according to one embodiment of thepresent invention therefore comprises a gate valve which solves thisproblem. In a general setup the dispensing device comprises acompartment for receiving a powdery material to be dispensed. Thecompartment comprises a tapered lower end with a gate valve dispensingopening. The dispensing opening is opened and closed by a gate acting aspart of a gate valve which is arranged such that it provides onlyminimum contact with the material stored in the compartment in that therim of the opening acts as a wiper for the material in contact with thegate so that the material in the compartment is not wasted. The gate ispressed firmly, e.g. by spring load, against a rim of the dispensingopening or an alternative edge such that no material may enter betweenthe rim of the opening and the gate. Good results have been achieved byan elastic gate closing the opening from a side. The gate is guided inappropriate guiding means guaranteeing that the gate is sufficientlyfirmly pressed against the opening at least at one side. In a preferredembodiment the gate is a relatively thin strip of elastic materialguided in at least one longitudinal slot extending radially from theopening. The strip of material is formed and arranged such that in theclosed position it tightly closes the opening. The dispensing device mayfurther comprise an agitator means to agitate the material stored in thecompartment. If appropriate the gate valve and the agitator meanscomprise standardized interface means to facilitate exchange of onedispensing device for a similar dispensing device. The compartment ofthe dispensing device may be designed such that it is hermeticallyclosable. In particular, the filling and the dispensing opening may besealingly closed in an appropriate way to allow storing of the materialwithin the dispensing device.

In a preferred embodiment the dispensing device comprises a compartmentto receive material to be dispensed having a generally cylindrical firstsection which leads into a generally conical second section. At the endof the second section the compartment comprises an opening which isarranged at an angle to the longitudinal axis of the first section andthe second section such that an oval shape of the opening results. Theopening can be sealed by a gate valve including a gate by which thepassage through the opening can be infinitely varied from fully closedto fully open. The position of the gate is adjusted by a first internalor external drive mechanism which is interconnected to the control unit.In the compartment, depending on the field of application, at least oneagitator is arranged rotatable and/or movable in the direction of acentre axis activated by a second internal or external drive mechanism.The agitator is preferably suitable to interact along the full length ofthe compartment with the material stored in the compartment. Goodresults have been achieved by a long thin wire-like structure extendingalong the inside contour of the compartment. The agitator is suitable tomix the material stored in the compartment and may help as a conveyormeans conveying the material to be dispensed through the opening at theend of the second section of the compartment. Depending on the materialto be dispensed at least one further agitator may be arranged within thecompartment moving in a direction similar or counter to the firstconveyor. The agitator thereby is suitable to take influence on themorphology, the distribution of grain of the material to be dispensed.The position of the agitator and the gate may be read out by sensormeans and the information provided to the control unit which isinterconnected to the first and the second drive mechanisms. It isobvious that the shape of the compartment may be different from theshape of the compartment in the preferred embodiment as long as it doesnot have any negative impact onto the functionality of the device.

To dispense material out of a dispensing device according to oneembodiment of the present invention in general the following steps areincluded

a) Interconnecting the dispensing device to a control unit;

b) If necessary activating the agitator to disperse the material storedin the compartment;

c) Opening the gate valve by retracting the gate until material startsto trickle through the opening of the gate valve and measuring theamount of material which has left by the weighing means and comparing itby the predetermined total amount of material to be dispensed;

d) If necessary activating, before or after the gate valve has beenopened, the conveyor means to support the trickling of the material; and

e) Adjusting the position of the gate to fully closed when thepredetermined amount of material to be dispensed is achieved.

One advantage of the dispensing device is that only a small number ofpieces having shapes that are easy to manufacture and maintain are indirect contact with the material to be distributed. The device isdesigned such that it can be made in mass production as a returnable ora disposable unit. By the herein disclosed invention it becomes possibleto provide to customers a prepacked set of dispensing devices containinga certain amount of repeatably used materials in powdery form. Thedispensing devices may then be stored in an appropriate storing devicewherefrom they may be automatically retrieved by an appropriate handlingdevice. To dispense material the handling device interconnects thedispensing device temporarily to a controller which controls the openingof the gate valve and the movement of the agitator and/or conveyormeans. A sensor means interconnected to the controller measures theamount of material passing through the gate valve. Dispensing errors arereduced in that each dispensing device may be marked by an appropriatetag, e.g. a radio frequency identification tag (RFID), which is read outby the controller before material is dispensed. Furthermore the tag maybe appropriate to hold and save information from the controller aboutthe amount of material dispensed from the dispensing device or the ageof the material stored in the dispensing device. In the storing device afurther reading device may be appropriate to read out information fromthe tags of the dispensing devices. Thereby it becomes possible to gaininformation about the amount and the condition of the material availableon stock.

BRIEF DESCRIPTION OF THE DRAWINGS

The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and there is no intention ofexcluding any equivalents of the features shown and described orportions thereof in the use of such terms and expressions, but it isrecognized that various modifications are possible within the scope ofthe invention claimed.

For a more complete understanding of the present invention, includingits features and advantages, reference is now made to the detaileddescription of the invention, taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is showing a dispensing device in a perspective view;

FIG. 2 the dispensing device according to FIG. 1 in an exploded view;

FIG. 3 the dispensing device according to FIG. 1 in a section view alongline DD;

FIG. 4 a controller with a dispensing device and a rack of dispensingdevices.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is now made in detail to embodiments of the invention,examples of which are illustrated in the accompanying drawings.

FIG. 1 shows a dispensing device 1 in a perspective view and FIG. 2shows the dispensing device 1 according to FIG. 1 in a disassembledmanner such that the internal of the dispensing device is visible. FIG.3 shows a section view along line DD through the dispensing device 1illustrated in FIGS. 1 and 2.

The dispensing device 1 comprises a housing 2 surrounding a compartment3 suitable to receive material to be dispensed. At the lower end thehousing 2 is a gate valve opening 4 which is when in its closed positionsealingly covered by a gate 5 which is supported by a rim of the opening4. The gate 5 is arranged retractable in a notch 6 extending radiallywith respect to the opening along the outside of the housing 2. Thenotch 6 acts as a guiding means for the gate 5. The blade like gate 5 ofthe illustrated embodiment is made out of an elastic material such asspring steel or a similar material which is resiliently interacts withat least a portion of the rim of the opening 4. The gate is operable somaterial is not pulled between the gate 5 and the housing 2.

As it can be seen in FIGS. 2 and 3, the gate 5 has a bend and is heldwithin the notch 6 by a sleeve 7 surrounding the lower part of thehousing 2. The sleeve 7 comprises a bayonet-type interlocking device 14(broadly, a standardized interface) by which the dispensing device 1 maybe securely attached to a corresponding interlocking device of a controlunit 20 (see FIGS. 3 and 4). The compartment 3 has an upper portionhaving a generally cylindrical shape and a lower portion having agenerally tapered conical shape in the region of the gate valve opening4 which has in the illustrated embodiment an oval shape. The dispensingdevice 1 has a sensor 41 adapted to retrieve information about thecondition of material contained in the dispenser, such as humidity,temperature or electric conductivity. The gate 5 is at its back endinterconnected to a bushing 8 arranged movably in vertical direction (z)along the outside of the first section of the housing 2. The bushing 8and the gate 5 are held in a closed position by a spring 9 which isarranged between the bushing 8 and an upper end of the housing 2. In theclosed position the opening 4 is sealingly closed by gate 5 such that nomaterial within the compartment 3 may uncontrollably exit through theopening 4. By moving the bushing 8 along the housing 2 (+z-direction),the spring 9 is compressed and the gate 5 is retracted such that theopening 4 is opened and material contained within the compartment 3 mayexit. The opening 4 may be opened infinitely variable amounts betweenfully closed and fully open by controlling the position of the gate 5.Because the gate is firmly pressed against the rim of the opening 4 therim acts as a wiper for the material stored in the compartment 3avoiding loss of material.

An agitator 10 is positioned in the compartment 3. The agitator 10comprises a drive shaft 11 rotatable around the central axis (z-axis) ofthe device 1. The drive shaft 11 comprises in the illustrated embodimenttwo shovels 12 reaching into the compartment 3. The drive shaft 11 inthe illustrated embodiment is rotatably mounted on the central axis ofthe device in a cover 13 which closes the rear end of the compartment 3.At its rear end the drive shaft 11 comprises a standardized interface bywhich the drive shaft may be interconnected to a clutch of a drive unit(see FIG. 4).

FIG. 4 shows a dispensing device 1 attached to a bracket 19 of acontroller 20 by the interlocking device 14. The control unit 20 furthercomprises a weighing device 21, a fork 22 which acts as a first drivemechanism suitable to displace the bushing 8 of the dispensing device 1in vertical direction (+z-direction) and thereby control the opening ofthe gate valve 4. The drive shaft 11 of the dispensing device isinterconnected to a second drive mechanism 23 which activates theagitator and/or the conveyor unit arranged within the compartment of thedispensing device 1 for conveying the material to the opening 4. On anexternal conveyor unit 24 for moving containers relative to thedispensing device 1, several containers 25 are arranged in line toreceive a certain amount of material 26 dispensed from the dispensingdevice 1. The controller 20 further comprises or is interconnected to acentral processing unit (CPU) 27 which controls and triggers the firstand the second drive mechanisms 22, 23 and receives and processes datafrom the sensors controlling the opening of the gate valve 4 and theagitator, respectively the conveyor unit within the dispensing device 1for conveying material to the opening 4. If appropriate the CPU 27further reads out and stores information from a tag 29 integrated in thedispensing device 1 about the material contained within the dispensingdevice 1. Depending on the field of application the CPU is operable toreceive and process a set of instructions, e.g. in the form of acomputer program, to automatically prepare predetermined amounts ofmaterials or a mixture of materials.

In a rack (not shown in the drawings) further dispensing devices 28 arestored. The further dispensing devices hold different materials on stockand may be interconnected to the control unit 20 either manually by handor by an automated handling system. To avoid errors, each of thedispensing devices 28 has a tag 29 which holds information about thematerial and the condition of the material stored in the dispensingdevice 28. The control unit 20 comprises means to read out and ifappropriate modify the information of the tag. Thereby it is possible tosignificantly reduce the risk of dispensing errors.

To dispense material into a container 25 the container 25 is movedunderneath the gate valve opening 4 and on the weighing device 21. Inthe illustrated embodiment the weighing device 21 is arranged such thatit interacts with the container 25 positioned to receive the material.In addition or alternatively a weighing device is incorporated in thebracket 19 and interacts with the dispensing device 1 to measure theamount of material exiting through the gate valve opening 4. Before thematerial is dispensed, the at least one measuring device 21 is reset. Ifnecessary the agitator within the compartment of the dispensing device 1is activated by the CPU to disperse the material stored in thecompartment. After that, the gate valve opening 4 is opened sufficientlyby retracting the gate 5 until material starts to trickle through theopening 4. The amount of material which has left the dispensing deviceis determined by the weighing device 21 and the information is madeavailable to the CPU 27 for comparison to the total amount to bedelivered. If necessary the conveyor means within the dispensing unit isactivated to support the trickling of the material. The opening of thegate valve 4 is adjusted by the CPU 27 by the position of the gate 5until the opening 4 is fully closed when the predetermined amount ofmaterial to be dispensed is achieved.

What is claimed is:
 1. A dispensing system for storing and dispensing atleast one material in solid form, the system comprising: a control unit;a plurality of interchangeable dispensing devices, each dispensingdevice including (a) a housing defining a compartment for the materialand an opening for dispensing the material from the device and (b) agate moveable between a closed position in which the gate blocks theopening and an open position in which the gate allows material in thecompartment to be dispensed through the opening; and a weighing deviceoperable to send signals to the control unit indicative of an amount ofmaterial dispensed from the system, wherein the control unit has aninterface and each of the interchangeable dispensing devices has acorresponding interface allowing it to be selectively and disengageablyinterfaced with the control unit to form an interfaced dispensingdevice, the movement of the gate of the interfaced dispensing devicebeing controlled by the control unit in response, at least in part, tothe signals from the weighing device, and wherein the housing of eachdispensing device has a longitudinal axis and the gate of eachdispensing device has an end, the end of the gate being moveablegenerally longitudinally of the housing to open and close the opening ofthe respective dispensing device.
 2. A dispensing system as set forth inclaim 1 wherein at least one of the dispensing devices comprises anagitator in the compartment, the control unit being adapted to controlthe agitator when the control unit is interfaced with said at least onedispensing device.
 3. A dispensing system as set forth in claim 2wherein the agitator comprises an elongate member connected to a drivemechanism, the drive mechanism being controlled by the control unit whenthe control unit is interfaced with said at least one dispensing device.4. A dispensing system as set forth in claim 1 wherein contact betweensaid at least one material in solid form and the dispensing system islimited to contact between said at least one material and the pluralityof interchangeable dispensing devices.
 5. A dispensing system as setforth in claim 1 wherein the weighing device is adapted to weigh acontainer positioned under the opening of the interfaced dispensingdevice.
 6. A dispensing device as set forth in claim 1 wherein theplurality of dispensing devices includes a first dispensing devicecontaining a first material in the respective compartment and a seconddispensing device containing a second material in the respectivecompartment, the first material being different from the secondmaterial.
 7. A dispensing device as set forth in claim 1 wherein theplurality of dispensing devices includes a first dispensing devicehaving a first size and a second dispensing device having a second size,the first size being larger than the second size.
 8. A dispensing deviceas set forth in claim 1 wherein the compartment of each dispensingdevice has a tapered lower section and the opening for each dispensingdevice is at a bottom of the respective tapered lower section.
 9. Adispensing device as set forth in claim 1 wherein each of the dispensingdevices comprises an information storage device readable by the controlunit and operable to store information about the material in thecompartment of the respective dispensing device.
 10. A dispensing deviceas set forth in claim 9 wherein the information storage device comprisesan RF ID tag.
 11. A dispensing device as set forth in claim 9 whereinthe stored information can be modified by the control unit.
 12. Adispensing system as set forth in claim 1 wherein the end of the gate ofeach dispensing device is interconnected to a bushing that is moveablegenerally longitudinally of the respective housing.
 13. A dispensingsystem as set forth in claim 1 wherein the opening of each dispensingdevice extends generally laterally outward with respect to thelongitudinal axis of the respective housing.
 14. A dispensing system asset forth in claim 1 wherein each dispensing device further comprises abiasing member biasing the respective gate toward its closed position.15. A dispensing system as set forth in claim 1 wherein each dispensingdevice comprises a sensor for sensing information about a condition ofthe material in the compartment of the dispensing device.